Traditional box springs have been made which comprise a generally rectangular wooden base including a pair of end rails and a pair of side rails and a plurality of intermediate rails extending from one side rail to the other side rail. A plurality of spaced coil springs arranged in a matrix are supported by the end rails and intermediate rails of the box spring frame. The lower end turns of each of the coil springs are stapled or otherwise secured to the wooden rails of the box spring frame. At the other end of each of the coil springs the upper end turns of the coil springs are secured to a wire grid comprising a plurality of intersecting wires arranged in a crisscrossing pattern. A generally rectangular upper border wire extends around the periphery of the grid. The box spring frame, coil springs and upper grid are encased in an upholstered covering in order to complete the box spring. Such a box spring has uniform characteristics throughout due to the uniform nature of the spring matrix. Other types of bedding or seating products have been made in the same manner.
Bedding or seating products including box springs have also been made with modular springs or other configurations of springs different than conventional coil springs. For example, U.S. Pat. No. 4,068,329 discloses a plurality of modular springs supported by a box spring frame. A conventional wire grid is attached to the tops of the modular springs. Additionally, U.S. Pat. No. 5,231,712 discloses a box spring having a plurality of sinuous-shaped springs supported by the frame members and an upper grid attached to the upper ends of the sinuous springs.
Additionally, bedding or seating products including box spring assemblies have been constructed with a plurality of wooden slats or members in the interior thereof. U.S. Pat. Nos. 414,390; 270,799 and 2,853,721 all disclose mattresses which include a plurality of solid members extending either lengthwise or widthwise inside the interior of the mattress. These solid members are either wooden or metallic and are located between adjacent convolutions of a row or column of coil springs. However, none of these patents discloses a box spring with a plurality of parallel wooden members located inside the interior of the box spring, a layer of springs underneath the wooden members and a separate layer of springs above the wooden members, thus dividing the box spring into separate layers.
Therefore, it has been one objective of the present invention to provide a bedding or seating product having multiple layers separated by a series of wooden interior slats.
It has been a further objective of the present invention to provide a bedding or seating product such as a box spring having two distinct layers with different firmness characteristics due to the nature of the springs comprising the different layers.
It has been a further objective of the present invention to provide a bedding or seating product such as a box spring having a peripheral edge of a different firmness to that of the interior of the product due to the nature of the springs and their location inside the product.